You have two sites you want to combine. Whether your brand purchased a new domain, acquired a competitor, or are merging two owned domains, migrating a website can seem like a daunting task. With so much at stake, it can be easy to put off. Any migration has a high possibility of experiencing a dip in rankings and traffic temporarily. But the benefits are worth it – with proper planning you can expect to see rankings and traffic recover, and possibly even improve with time.

When merging two domains owned by the same brand, such as migrating a blog on a subdomain over to the main site, you’ll likely see a long term increase in rankings and traffic, and people visiting your site will be able to find the content they’re looking for easier. Plus, there won’t be two different domains to worry about anymore.

In the case of one brand buying a competitor, or otherwise merging two previously unaffiliated domains, the merger can translate to increased authority, rankings, traffic, and conversions for the existing site (not to mention, one less competitor!). However, you may not always want to merge the new website into the existing one, especially if the new website is the stronger domain.

Here are a few things to consider when deciding which site to merge into the other:

Authority: If you’re trying to decide which site to keep and which to redirect, it’s best to keep the stronger website and redirect the weaker one. This helps keep the most traffic and rankings and likely means upsetting fewer visitors. Compare each domain to determine which one is stronger: number of pages, linking root domains, ranking keywords (on page 2 or higher). Use the Domain vs Domain feature in SEMrush to compare the sites side by side. Also use existing analytics data to compare organic traffic, conversions, revenue, and any other valuable metrics.

Branding: Will you want users to find the new websites or will they adopt your website’s branding and have redirects implemented? You may decide to implement a grace period in which visitors to the new websites are notified about the acquisition before redirects are put in place, especially if the acquisition occurs before you’re prepared to implement redirects.

Content: Will all content be migrated? Are any pages going to be eliminated? Will new pages need to be created? Is there a major difference between the types of content on the two websites (video, text, images)? Knowing what you have to work with can help make this decision easier, or at least help inform your redirect strategy.

Regardless of the type of migration you’re going through, a solid plan is your best bet at achieving a successful migration. Follow the steps in each of three checklists below (pre-migration, during-migration, post-migration) and you’ll be set up for a smooth merger. To get started download the Website Migration Checklist:

Pre-Launch Migration Checklist

Crawl the site. Use Screaming Frog (or a similar tool) to crawl the entire site before you make any changes. This data will show you all of the URLs that currently exist and important information about each, like which have internal links pointing to them. You can save this data to compare to the site after the migration. For example, if you discover that you’ve lost a lot of traffic after the migration you can compare the new site to this previous data and see if any URLs were mistakenly removed.

Map new URLs to existing URLs. This is the most important step of a migration and can be the difference between a successful site migration or merger and a migration riddled with problems. Find the corresponding URL on the existing website for each new URL that is going to be migrated over. If two pages are similar enough one should be migrated to the other to avoid duplicate content issues. If there isn’t a clear 1:1 redirect path, there may need to be a new architecture to accommodate new content. In this case, map out the new top pages using analytics data and determine where pages can be consolidated and where they may fall on the new navigation.

Identify pages to be eliminated. Any pages that you want to fall completely off the map should return a 404 error, just be sure you aren’t linking to the broken URL elsewhere on the new site. If you have a URL that you don’t want to keep but that URL has links pointing to it (maybe it’s a service you don’t offer anymore), make sure to 301 redirect so you can keep most of that link value.

Identify pages to be created. Create a new page for any content that doesn’t have a corresponding URL. This helps keep the rankings of the site being migrated.

Benchmark metrics. Include rankings, pages indexed, organic traffic, organic conversions, organic revenue, and any other metrics that may be important to either website. Expect an initial drop in rankings after the migration (which should recover), and plan the migration during a historically slower period. A variety of free and paid tools exist for benchmarking, including Google Analytics and Google Search Console (important to check this ahead of time as GSC data currently only goes back 90 days), Omniture, and SEMrush.

Make a custom 404 page. The 404 page should have a link to an existing target page (not the home page) to keep people on the site.

Register Google Search Console. Register the new website’s Google Search Console profile under the existing account. Include both www and non-www and http and https versions of each site.

Set up a new robots.txt file. The new robots.txt file should include areas Googlebot can and cannot crawl once the migration takes place.

During Migration Checklist

Ensure Google Analytics (and any other tracking software) is in place and collecting data. Make sure all new URLs and redirected URLs have the existing Google Analytics code in place and metrics are being tracked. Using the existing Google Analytics account is recommended in order to keep historical data for measuring later.

Annotate the launch in Google Analytics and other analytics programs. This helps to quickly answer any questions in the future and provides context for benchmarking.

Test URL redirects. Make sure each URL is redirecting to the proper new URL based off the redirect map you created. Perform a site lookup (site:www.yoursite.com) to ensure the redirects are properly indexed.

Update internal links. Update all links pointing to a page that is now being redirected. While the 301 redirect will also pass these links to their new location, there’s the risk of having a redirect loop or overloading crawler resources. Point all internal links directly to their new, proper location with relevant anchor text.

Update XML Sitemap. XML sitemaps inform search engines about the content on a site. Creating a new XML sitemap helps Google rediscover the site’s content in its new location. Submit the updated XML sitemap to Google Search Console and add a link to the sitemap in the robots.txt file. This helps make Google and other search engines aware of all new URLs, including URLs that aren’t included anymore.

Submit a change of address. Like the Post Office, Google likes to know where the content it indexed is moving to. Submit a change of address ONLY for the migrated website within Google Search Console. This makes it easier for Google to understand where to find the new location of the domain’s content. Do not do this for the domain that isn’t moving.

Post-Launch Migration Checklist

Monitor errors. Monitor the error reports in Google Search Console weekly (or even more frequently) to stay on top of any issues. Pay close attention to 404 and 500-level errors, errors with the sitemap file, crawl rate issues, and HTML problems such as duplicate content or title tags and meta descriptions that are too short, too long, or missing. Also monitor important site metrics in Google Analytics (such as organic and referral traffic and conversions) and measure them against the benchmarks you took before the migration.

Check the number of indexed pages. This number might drop for a bit after the migration, but with the 301 redirects the number should climb up to normal or higher if new pages were created. If the number of indexed pages stays low there could be an issue with the redirects. Also make sure pages that were eliminated aren’t still being indexed. Check in Google Search Console and via a site lookup (site:www.yoursite.com).

Perform an architecture audit. In addition checking the above and making sure those 301 redirects are in place, make sure the rest of the site navigation is as it should be and there weren’t any other errors. Include the following:

Title tags, meta descriptions, and H1s are correct (and not missing or duplicated)

Any noindex/nofollow and robots.txt disallow directives have been removed

Navigation and images are crawlable and indexable (and there isn’t any duplicate content)

Structured markup (schema.org) is implemented and correct on all applicable elements

Mobile brand breadcrumbs are in place on all pages

Site speed (desktop and mobile) is high

This is a good time to crawl the whole site again, and compare the two sets of data to make sure the changes are what you expect to see. If any URLs have lost significant traffic you’ll be able to check if content was unintentionally removed.

Update external links. Contact external blogs, news websites, and other linking resources to inform them of the new link location and ask for any links to be updated. This helps ensure that the authority the migrated domain had built will be passed along to the existing site. Prioritize these links by focusing on the top tier pages and working your way down to lower tier pages.

Re-submit the link disavow file. After the migration, all of the links that pointed to the migrated site will be now pointing to the existing site – good and bad. If either site experienced any issues with bad links they may have created and submitted a disavow file to prevent Google and other search engines from associating their site with these bad links (and reducing the risk of a penalty).

If this is the case, combine both disavow files, include any new links to be disavowed, and re-submit the file in Google Search Console. Disavow files are overwritten each time one is submitted, so combining them prevents losing any previous data.

If you’ve taken all of the precautions in the pre-migration phase and have a solid launch plan, the post-migration phase should be simple. Keep an eye on things and be prepared for a dip in rankings and traffic, and you should start to see improvements within a few weeks. With the right preparation, you should expect to see rankings and traffic improve over what they were originally. Good luck!